Container end wall construction

ABSTRACT

Increased resistance against internal pressure in an end wall for a highly pressurized container is provided by an outwardly descending substantially planar portion at the periphery of a concavely domed central panel where the central panel meets a substantially vertical countersink wall.

I United States Patent [191 [11] 3,731,838 Gedde [451 May 8, 1973 [541CONTAINER END WALL 3,360,158 12/1967 Klein 220/66 CONSTRUCTION FOREIGNPATENTS OR APPLICATIONS [75] Inventor: Erik Gedde, Park Ridge, Ill.289,069 3/1965 Netherlands ..220/67 [73] Assignee: American Can Company,Green- Wich, D- Primary ExaminerAllen N. Knowles [22] Filed: Apt 8, 1971Assistant Examiner-Gene A. Church Attorney-Robert P. Auber, George P. Zehmer and 1 PP 132,518 Leonard R. Kohan 52 us. Cl ..220/67 1571 ABSTRACT[51] IntCL ..B65d 7/42 Increased resistance against internal pressure inan [58] Field 01' Search .220/66, 67; 229/5.5 end wall for a highlypressurized Container is provided by an outwardly descendingsubstantially planar por- {56] References cued tion at the periphery ofa concavely domed central UNITED STATES PATENTS panel where the centralpanel meets a substantially vertical countersink wall. 3,339,793 9/1967Gerlovich ..220/66 2,579,466 12/1951 Birkland ....220/67 X 3 Claims, 2Drawing Figures 2,613,015 10/1952 Keating..... ....220/67 X 2,795,3506/1957 Lapin ..220/67 X Patented May 8, 1973 3,731,838

INVENTOR.

.qmmz W CONTAINER END WALL CONSTRUCTION It is known that end walls ofpressured cans, especially highly pressurized cans such as those of theaerosol type, sometimes buckle due to internal pressure.

Accordingly, it is a primary object of the present invention to providean improved end wall structure for pressurized containers that iscapable of withstanding substantially higher pressures than those whichcan be withstood by comparable conventional end wall structures.

Another object is to provide an end wall structure for pressurizedcontainers which affords improved resistance to buckling withoutchanging the weight or type of sheet metal used.

Still another object is to provide an improved container end wall whichaffords economies in pressure can production, especially by allowing theuse of lighter weight plate while at the same time maintaining strengthrequirements.

This invention relates to containers adapted to withstand highpressures, and more particularly, it involves an improved end wallstructure for such con-- tainers. Specifically, the end wallconstruction of this invention comprises a generally concavely domedcentral panel whose periphery is an outwardly descending substantiallyplanar portion adjoining a peripheral vertical countersink wall whichmerges with and terminates in a peripheral U-shaped flange for attachingthe end wall to a container. Within the purview of this invention is anend wall construction by itself, as secured to a container body as by adouble seam, and as part of or integral with a container body. I

The objects and advantages of the invention will be apparent as itbecomes better understood from the foliowing description which, whenread in connection with the accompanying drawings, discloses a preferredembodiment of the invention.

In the drawings:

FIG. 1 is an elevational view, partially in section, of a containerembodying the present invention.

FIG. 2 is an enlarged sectional fragmentary view showingthe end wall ofFIG. 1.

Referring to the drawing in detail, FIG. 1 shows a pressurizedcontainer, generally designated 10, formed of a suitable material suchas sheet metal and comprising a cylindrical body 12, a convex top wall14, a dispensing valve'l6 and a concave bottom or end wall generallydesignated 18. The bottom wall is secured to the lower edge of body 12by a folded seam or bead 20 in a conventional manner. Within the purviewof this invention are can constructions wherein the bottom and body aresecured by other means and constructions wherein the bottom and the endwall are integral, i.e. one piece.

FIG. 2 shows an enlarged sectional portion of end wall 18 of FIG. 1 andclearly illustrates the improvement of this invention. Specifically,FIG. 2 shows end wall 18 comprised of a generally concavely domedcentral panel 22 having at its periphery an outwardly descendingsubstantially planar portion 24, adjoining a peripheral substantiallyvertical counter-sink wall 26 which merges with and terminates in aperipheral U- shaped flange 28. for attaching the end wall to acontainer body.

Concavely domed central panel 22 has a relatively large radius ofcurvature R extending from a center point (not shown), and the panelsconcavely domed central portion blends into its peripheral outwardlydescending planar portion 24 at a point or locality designated BP (BlendPoint). Planar portion 24 merges with countersink wall 26 at an areaalong an are formed by relatively small radius of curvature r. Planarportion 24 is shown at an angle blending with the domed portion of thecentral panel 22 and merging with countersink wall 26. The angle isabout 40 and is formed on the one hand by one of the surfaces of planarportion 24, preferably its inner surface, tltat surface being tangent tothe are formed by radius of curvature r, and on the other by a linedrawn horizontally through the upper portion of vertical countersinkwall 26 (shown) and extended horizontally through a correspondingportion of a countersink wall on the opposite, i.e. right, side of theend wall (not shown). This horizontal line is substantially parallel toa horizontal line which could be drawn along the bottom of the U-shapedflanges of vertically standing container 10 (one flange, 28, is shown).The angle could also, of course, be formed by an imaginary line extendedor drawn out from a surface, preferably the inner surface, of planarportion 24 so that the line meets the horizontal line which, asaforementioned, could be drawn along the bottom of flanges 28 ofcontainer 10.

The angle formed by planar portion 24. and the horizontal line runningfrom countersink wall 26 can be any angle less than but practicallyspeaking the angle generally is from about 35 to 45 and preferably isfrom about 38 to 42. The most preferred and most advantageous angle isabout 40.

The improvement of this invention resides in providing the end wall withplanar portion 24 itself and in providing that portion with theaforementioned particular angle, for it is the combination of these,i.e. the planar portion and its angle, that provides the end withsignificantly improved resistance against buckling or bursting due tohigh internal pressure. For example, tests of end walls made of 107pound TU tinplate and having the same thickness and diameter, have shownthat whereas a conventional end wall having a hemispherical profile hasa buckle resistance of about to 200 psi, and, whereas a commerciallysuccessful ellipsoidal or generally concavely domed end wall formed oftwo merging arcs such as described in US. Pat. No. 3,360,158 issued toA. J. Klein on Dec. 26, 1967, has a buckle resistance of about 260 psi,an end wall of this invention, for example, having a 45 angled planarportion, has a buckle resistance of about 360 psi.

The amount of buckle resistance that can be provided by the end wall ofthis invention varies with the angle of planar portion 24. This is seenfrom results of the aforementioned tests, shown in the table below:

Buckle Resistance End No. Angle (P.S.l.)

Although, as previously indicated, angles under 90 can be employed, ithas been found advantageous to use as small an angle as practicableunder the circumstances. This is because larger angles protrude moredeeply into the interior of the can. This reduces container capacity andrequires more metal to manufacture the end.

The end wall construction of this invention can be manufactured with anysuitable material such as for example steel, tin free steel, oraluminum. As previously seen, satisfactory results were obtained using107 pound TU tinplate. Satisfactory results can also be obtained whenaluminum is employed. For instance, tests have shown that 40 angledaluminum end walls in three piece cans having soldered side seams hadbuckle resistances averaging about 315 psi, and two piece drawn aluminumcans having 40 angled ends had buckle resistances of from about 265 to280 psi. This latter example can be compared to buckle resistances ofabout 160 psi for presently commercially successful two piece drawnaluminum cans having ellipsoidal ends of two merging arcs as disclosedin the aforementioned U.S. Pat. Number 3,360,158.

In the inventioned disclosed herein, there is presented an improved endwall construction which, although fabricable of a lighter weight platematerial, is capable of withstanding higher pressures than withstood bycomparable conventional hemispherical or ellipsoidal end wallconstructions.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the form of the end withoutdeparting from the spirit and scope of the invention or sacrificing allof its material advantages, the hereinbefore described being merely apreferred embodiment thereof.

lclaim:

1. An end wall for a container adapted to withstand high internalpressure comprising a generally concavely domed central panel whoseperiphery is an outwardly descending substantially planar portionadjoining a peripheral, vertical countersink wall which merges with andterminates in a peripheral U-shaped flange for attaching said end wallto said container.

2. The end wall of claim 1 wherein said end wall is secured to acontainer by a double seam formed by said U-shaped flange beinginterfolded with a peripheral flange of said container.

3. The end wall of claim 1 wherein said end is integral with saidcontainer.

1. An end wall for a container adapted to withstand high internalpressure comprising a generally concavely domed central panel whoseperiphery is an outwardly descending substantially planar portionadjoining a peripheral, vertical countersink wall which merges with andterminates in a peripheral U-shaped flange for attaching said end wallto said container.
 2. The end wall of claim 1 wherein said end wall issecured to a container by a double seam formed by said U-shaped flangebeing interfolded with a peripheral flange of said container.
 3. The endwall of claim 1 wherein said end is integral with said container.